Clinical relevance of measurement of brain natriuretic peptide and N-terminal pro-brain natriuretic peptide in pediatric cardiology

Cardiovascular Outcomes in Children with Multisystem Inflammatory Syndrome Treated with Therapeutic Plasma Exchange

Background: Multisystem inflammatory syndrome in children is a new, rare, post-infectious complication of SARS-CoV-2 infection in children. The aim of this study was to display the role of therapeutic plasma exchange on cardiovascular outcomes in children with multisystem inflammatory syndrome. Methods: This study included children who met the diagnostic criteria for multisystem inflammatory syndrome and who were admitted to the intensive care unit. This is a prospective single-center study conducted between August 2020 and September 2021. Subjects had cardiac involvement which was defined as elevated troponin I, abnormal electrocardiographic and echocardiographic findings. Patients were followed by a pediatric cardiologist throughout the intensive care unit stay and after discharge for 12 months. Patients were divided into two groups which received therapeutic plasma exchange and which did not. Results: 38 children were included in this study. There were 16 patients in the no plasma exchange group and 22 patients in the plasma exchange group. The two groups were similar in age, sex, leucocyte, thrombocyte count, neutrophil percentage, hemoglobin, C-reactive protein, erythrocyte sedimentation rate, alanine aminotransferase, albumin, ferritin, fibrinogen, D-dimer, IL-6, troponin I, number of electrocardiographic abnormalities and patients with mitral valve regurgitation detected at admission (p > 0.05). There was no significant difference between the two groups in terms of duration of normalization of electrocardiographic abnormalities and disappearance of mitral valve regurgitation (p > 0.05). Duration of normalization of troponin I (2, IQR 1−4, versus 5, IQR 3−9 days; p = 0.044) and length of hospital stay (7, IQR 6−10, versus 13, 8−20 days; p = 0.001) was longer in the plasma exchange group. Conclusions: We did not observe any significant improvement in children having undergone plasma exchange as compared to children who did not. On the opposite, their length of hospital stay and time to troponin I normalisation were even longer. Some baseline differences in cardiac attainment severity may partly explain this finding.

NT-proBNP levels and cardiopulmonary function in children with sickle cell disease

Patients with sickle cell disease (SCD) are living longer and subsequently more apt to develop cardiopulmonary dysfunction. N-terminal pro-brain natriuretic peptide (NT-proBNP) levels have been used in adults with SCD to assess for pulmonary hypertension and mortality. While the incidence of PH is low in pediatrics, it is reasonable to presume that NT-proBNP levels can be used to assess risk for the development of cardiopulmonary morbidity. We hypothesized that NT-proBNP levels would be increased in patients with SCD compared to age-adjusted healthy children; additionally, these levels would be associated with labs indicative of hemolysis and would demonstrate evidence of obstructive lung disease and cardiac dysfunction. We retrospectively evaluated patients with SCD, 8-18 years old, at a large, tertiary care children's hospital. NT-proBNP levels were assessed in correlation with hemolytic lab work, spirometry, and echocardiographic data. The age group 8-14 years old, 75% of our cohort's population, had a median NT-proBNP of 70 pg/ml, greater than their age-adjusted counterparts (52 pg/ml). NT-proBNP levels were associated with an increased degree of hemolysis when compared with hemoglobin (Hb) (r = -0.43, p < .0001), reticulocyte count (r = .25, p = .01) and lactate dehydrogenase levels (r = .47, p < .0001). An inverse trend was found between NT-proBNP and spirometric data. Finally, a positive correlation was found between NT-proBNP and diastolic left ventricular size (r = .28, p = .047]. The correlations found suggest that NT-proBNP may be used prospectively to identify patients with SCD at increased risk for the development of cardiopulmonary dysfunction.

Pathophysiology and molecular signalling in pediatric heart failure and VAD therapy

Heart Failure (HF) is a progressive clinical syndrome characterized by molecular and structural abnormalities that result in impaired ventricular filling and a reduced blood ejection. In pediatric patients, HF represents an important cause of morbidity and mortality, but underlying cause, presentation and disease course remains unclear in many cases. It is evident that a child is not a "small adult" and findings are not comparable. The adoption of a standardized clinical and surgical tools as well as increased biomolecular research and therapeutic trials targeting pediatric patients with HF would greatly improve the management of this special class of patients. This review examines the most current information about the pathophysiology and molecular mechanisms related to HF in children to identify gaps in our knowledge base to further improve clinical care and outcomes.

Plasma B-type natriuretic peptide cannot predict treatment response to ibuprofen in preterm infants with patent ductus arteriosus

Plasma B-type natriuretic peptide (BNP) is a useful marker for diagnosis of hemodynamically significant PDA (hsPDA) and serial BNP measurement is also valuable for monitoring treatment response. This retrospective study was performed to evaluate whether plasma BNP level can predict treatment response to ibuprofen in preterm infants born at <30 weeks of gestation with hsPDA. Plasma BNP was measured before (baseline) and 12 to 24 h after (post-treatment) completion of the first (IBU1) and second (IBU2) course of ibuprofen. We compared the BNP levels of responders (closed or insignificant PDA) with those of non-responders (hsPDA requiring further pharmacologic or surgical closure) to each course of ibuprofen. The treatment response rates for IBU1 (n = 92) and IBU2 (n = 19) were 74% and 26%, respectively. In IBU1, non-responders had lower gestational age and birth weight than responders (both, P = 0.004), while in IBU2, non-responders had lower birth weight (P = 0.014) and platelet counts (P = 0.005) than responders; however, baseline BNP levels did not differ significantly between responders and non-responders in either IBU1 (median 1,434 vs. 1,750 pg/mL) or IBU2 (415 vs. 596 pg/mL). Post-treatment BNP was a useful marker for monitoring treatment efficacy of IBU1 and IBU2 for hsPDA with a cut-off value of 331 pg/mL (P < 0.001) and 423 pg/mL(P < 0.010), respectively. We did not identify a cut-off baseline BNP level that could predict treatment response to ibuprofen in preterm infants with hsPDA.

Analytical barriers in clinical B-type natriuretic peptide measurement and the promising analytical methods based on mass spectrometry technology

B-type natriuretic peptide (BNP) is a circulating biomarker that is mainly applied in heart failure (HF) diagnosis and to monitor disease progression. Because some identical amino acid sequences occur in the precursor and metabolites of BNP, undesirable cross-reactions are common in immunoassays. This review first summarizes current analytical methods, such as immunoassay- and mass spectrometry (MS)-based approaches, including the accuracy of measurement and the inconsistency of the results. Second, the review presents some promising approaches to resolve the current barriers in clinical BNP measurement, such as how to decrease cross-reactions and increase the measurement consistency. Specific approaches include research on novel BNP assays with higher-specificity chemical antibodies, the development of International System of Units (SI)-traceable reference materials, and the development of structure characterization methods based on state-of-the-art ambient and ion mobility MS technologies. The factors that could affect MS analysis are also discussed, such as biological sample cleanup and peptide ionization efficiency. The purpose of this review is to explore and identify the main problems in BNP clinical measurement and to present three types of approaches to resolve these problems, namely, materials, methods and instruments. Although novel approaches are proposed here, in practice, it is worth noting that the BNP-related peptides including unprocessed proBNP were all measured in clinical BNP assays. Therefore, approaches that aimed to measure a specific BNP or proBNP might be an effective way for the standardization of a particular BNP form measurement, instead of the standardization of “total” immunoreactive BNP assays in clinical at present.

Evaluation of NT-proBNP in children with heart failure younger than 3 years old

INTRODUCTION

Heart failure (HF) is characterized by neuroendocrine activation. The cardiac natriuretic hormones, including atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), together with their related pro-peptides (proANP and proBNP) represent a group of peptide hormones produced by the heart. A normal NT-proBNP level has a high negative predictive value for heart failure. The use of NT-proBNP testing is helpful in diagnosing acute HF in the emergency care setting, allowing an early and optimal treatment. The purpose of this study is to assess the prognostic value of NT-proBNP in heart failure in children younger than 3 years old and to establish whether it correlates with the NYHA/Ross functional class and left ventricle systolic function.

METHODS

We enrolled 24 consecutive children with HF due to congenital heart diseases and dilated cardiomyopathy. The serum levels of NT-proBNP were measured, all patients underwent echocardiography and left ventricle ejection fraction was calculated.

RESULTS

The highest median value of NT-proBNP was recorded in patients with cyanotic heart diseases (248.0 fmol/mL), p = 0.610. NT-proBNP had a negative correlation with the ejection fraction of the left ventricle: Spearman's rank correlation coefficient was -0.165.

CONCLUSIONS

NT-proBNP levels correlate with the severity of HF in infants and small children younger than 3 years old with heart failure due to congenital heart diseases and dilated cardiomyopathy.

The Utility of Brain Natriuretic Peptide in Pediatric Cardiology: A Review

OBJECTIVE

The aim of this article is to evaluate the clinical utility of brain natriuretic peptide in pediatric patients, examining the diagnostic value, management, and prognostic relevance, by critical assessment of the literature.

DATA SOURCES

In December 2015, a literature search was performed (PubMed access to MEDLINE citations; http://www.ncbi.nlm.nih.gov/PubMed/) and included these Medical Subject Headings and text terms for the key words: "brain natriuretic peptide," "amino-terminal pro-brain natriuretic peptide," "children," "neonate/s," "newborn/s," "infant/s," and "echocardiography."

STUDY SELECTION

Each article title and abstract was screened to identify relevant studies. The search strategy was limited to published studies in English language concerning brain natriuretic peptide/amino-terminal pro-brain natriuretic peptide in pediatric patients.

DATA EXTRACTION

Data on age, gender, type of clinical condition, brain natriuretic peptide assay method, cardiac function variables evaluated by echocardiography, and prognosis were extracted.

DATA SYNTHESIS

Brain natriuretic peptide reference values in healthy newborns, infants, and children are presented. Brain natriuretic peptide diagnostic accuracy in newborns, infants, and children suspected to have congenital heart defects is discussed, and brain natriuretic peptide prognostic value reviewed. The data suggest that the determination of brain natriuretic peptide levels improves the diagnostic accuracy in the assessment of heart disease in the pediatric population. Brain natriuretic peptide assay may increase the accuracy of neonatal screening programs for diagnosing congenital heart defects. Echocardiographic variables correlated to brain natriuretic peptide levels. Additionally, brain natriuretic peptide levels predicted adverse outcomes in the postoperative period.

CONCLUSIONS

Brain natriuretic peptide assessment is a reliable test to diagnose significant structural or functional cardiovascular disease in children. In the integrated follow-up of these cases, several physiologic and clinical variables must be considered; brain natriuretic peptide may be an additional helpful marker. Nevertheless, larger prospective studies are warranted to elucidate the true prognostic value of brain natriuretic peptide in pediatric patients.

NT-proBNP in Children With Left to Right Shunt and Dilated Cardiomyopathy

Background

B-type natriuretic peptide (BNP) levels are elevated in children with congenital heart disease involving a left-to-right shunt (LRS) and are also raised in dilated cardiomyopathy (DCM). As far as we know, there are few reports in the literature comparing the change of the NT-proBNP in LRS and DCM especially in the pediatric age group.

Objectives

The aim of the study was to compare the changes of the NT-proBNP in pediatric patients with LRS and DCM. Correlation between the levels of NT-proBNP and the echocardiographic parameters in both groups was determined.

Patients and Methods

A total of 30 children (13 males and 17 females) participated in the study. There were 11/30 (36.7%) DCM and 19/30 (63.3%) LRS. The control group consisted of 44 healthy infants and children. Manifestations of heart failure (decompensation) were recorded. The NT-pro BNP levels were measured. The following Echo parameters were assessed: systolic function (ejection fraction and fraction shortening), pulmonary to systemic flow (Qp/Qs) in LRS, pulmonary flow and pulmonary artery pressure (SPAP) and LV diastolic function (E-wave, A-wave, E/A ratio and deceleration time).

Results

Clinically 17/30 (56.7%) (11 of the LRS and 5 of the DCM) were decompensated. Significant shunt was present in 15/19 (78.9%) in LRS. Systolic dysfunction was presented in 5/30 (16.7%) cases (4 patients were DCM and one case was LRS). Two types of diastolic dysfunction, impaired relaxation in 5/22 (22.7%) patients and restrictive-like filling pattern in 5/16 (31.2 %) were observed. The NT-Pro BNP level was significantly elevated 11 and 16 times in the LRS and DCM groups respectively. Negative significant correlations were observed between the levels of NT-ProBNP and the following echo variables; EDD, LAD, E wave and E/A ratio in the LRS patients. Positive significant correlations were observed between the levels of NT-ProBNP and the following echo variables; PAP and QP/QS in the LRS. Both the PAP and QP/QS were higher in the elevated NT-Pro BNP group compared to the normal level group. The NT-Pro BNP level was elevated in all 17/30 (56.7%) decompensated patients (11 were LRS, 6 were DCM) (P = 0.002). However, the level was elevated in only 7/13 (23.3%) of the compensated patients (3 were LRS, 4 were DCM) (P = 0.002). The NT-Pro BNP level was also elevated in 18/19 cases with pulmonary hypertension (P = 0.01). Finally, we conclude that the NT-ProBNP level is elevated in both LRS and DCM in pediatric age. This elevation is more remarkable with heart failure and increased PAP in both diseased groups. The level was also elevated and correlated to Qp/Qs in the LRS patients.

Conclusions

So, we recommend the use of NT-ProBNP as a routine marker for following up patients with heart failure and pulmonary hypertension in LRS and DCM.

B-Type Cardiac Natriuretic Peptides in the Neonatal and Pediatric Intensive Care Units

During the last decade, interest in the brain natriuretic peptide (BNP) and N-terminal probrain natriuretic peptide (NT-proBNP) in the pediatric population has progressively increased. The aim of this article is to provide an up to date review of evidences regarding the use of BNP/NT-proBNP in pediatrics, with a particular focus on neonatal intensive care and congenital heart disease. The potentialities of the BNP have been demonstrated in multiple settings, particularly: the screening of congenital/acquired heart disease (CHD) versus pulmonary disease; the evaluation of CHD severity (grade of heart failure, degree of left-to-right shunts); the management of children undergoing cardiac surgery; and monitoring premature infants with patent arterial duct. BNP/NT-proBNP values may be considered an easy and relatively low cost additional diagnostic and prognostic tool. Interpretation of BNP values in children requires attention to important factors, including: laboratory methods, the type of cardiac defect, its severity, and the presence of extracardiac conditions. Of these, the hemodynamic characteristic of CHD and physiologic variations of BNP values occurring during the first weeks of life play a major role. The current evidences in favor of BNP use are mainly derived from single-center, nonrandomized studies, and cost-effectiveness analysis are still lacking. As such, despite sufficient evidences supporting the diagnostic and prognostic potentialities of BNP, these findings should be reinforced by multicenter, randomized studies specifically designed to evaluate outcomes and cost-effectiveness. In addition, standard consensus documents/guidelines, that are currently lacking, are warranted for a more systematic use of BNP in the pediatric age.

State of the art of immunoassay methods for B-type natriuretic peptides: An update

The aim of this review article is to give an update on the state of the art of the immunoassay methods for the measurement of B-type natriuretic peptide (BNP) and its related peptides. Using chromatographic procedures, several studies reported an increasing number of circulating peptides related to BNP in human plasma of patients with heart failure. These peptides may have reduced or even no biological activity. Furthermore, other studies have suggested that, using immunoassays that are considered specific for BNP, the precursor of the peptide hormone, proBNP, constitutes a major portion of the peptide measured in plasma of patients with heart failure. Because BNP immunoassay methods show large (up to 50%) systematic differences in values, the use of identical decision values for all immunoassay methods, as suggested by the most recent international guidelines, seems unreasonable. Since proBNP significantly cross-reacts with all commercial immunoassay methods considered specific for BNP, manufacturers should test and clearly declare the degree of cross-reactivity of glycosylated and non-glycosylated proBNP in their BNP immunoassay methods. Clinicians should take into account that there are large systematic differences between methods when they compare results from different laboratories that use different BNP immunoassays. On the other hand, clinical laboratories should take part in external quality assessment (EQA) programs to evaluate the bias of their method in comparison to other BNP methods. Finally, the authors believe that the development of more specific methods for the active peptide, BNP1-32, should reduce the systematic differences between methods and result in better harmonization of results.

Changes in NT-proBNP in young children with congenital heart malformations

OBJECTIVE

We measured serum NT-proBNP levels in 2 groups of young patients (0-36 months) with congestive heart failure (CHF) secondary to congenital heart malformations (CHM).

METHODS

The first group included 23 patients prior to surgery for heart malformations. The second group included 12 patients with CHM within 24 hours post-operation. NT-proBNP levels were measured by an enzyme-linked immunosorbent immunoassay (ELISA) using the Chem Well 2910 (Awareness Technology Inc.) automated analyzer.

RESULTS

NT-proBNP values were 4 times higher in patients with unoperated CHM compared to healthy controls (P < 0.001), and 12 times higher in patients with CHM 24 hours after surgery compared to controls (P = 0.0001).

CONCLUSIONS

These results demonstrated significant changes in NT-proBNP concentrations before and after surgery to correct congenital heart malformations.

C-type natriuretic peptide plasma levels are reduced in obese adolescents

The high prevalence of obesity in children may increase the magnitude of lifetime risk of cardiovascular disease (CD). At present, explicit data for recommending biomarkers as routine pre-clinical markers of CD in children are lacking. C-type natriuretic peptide (CNP) is assuming increasing importance in CD; in adults with heart failure, its plasma levels are related to clinical and functional disease severity. We have previously reported five different reference intervals for blood CNP as a function of age in healthy children; however, data on plasma CNP levels in obese children are still lacking. Aim of this study was to assess CNP levels in obese adolescents and verify whether they differ from healthy subjects. Plasma CNP was measured in 29 obese adolescents (age: 11.8 ± 0.4 years; BMI: 29.8 ± 0.82) by radioimmunoassay and compared with the reference values of healthy subjects. BNP was also measured. Both plasma CNP and BNP levels were significantly lower in the obese adolescents compared to the appropriate reference values (CNP: 3.4 ± 0.2 vs 13.6 ± 2.3 pg/ml, p<0.0001; BNP: 18.8 ± 2.6 vs 36.9 ± 5.5 pg/ml, p=0.003). There was no significant difference between CNP values in males and females. As reported in adults, we observed lower plasma CNP and BNP levels in obese children, suggesting a defective natriuretic peptide system in these patients. An altered regulation of production, clearance and function of natriuretic peptides, already operating in obese adolescents, may possibly contribute to the future development of CD. Thus, the availability of drugs promoting the action of natriuretic peptides may represent an attractive therapeutic option to prevent CD.

Aminoterminal pro-B-type natriuretic peptide: heart or lung disease in the neonate?

OBJECTIVES

B-type natriuretic peptides have been shown to enable differentiation between heart and lung diseases in adults and children. In neonates, the role of natriuretic peptides for diagnosis of congenital heart defect (CHD) is not yet ascertained. The purpose of this single-center prospective study was to investigate aminoterminal B-type natriuretic peptide concentrations and their time courses during the first 5 days of life in neonates with CHD compared with neonates with respiratory distress.

DESIGN

Single-center prospective study.

SETTING

Tertiary-care neonatal ICU.

PATIENTS

Aminoterminal B-type natriuretic peptide levels of 40 neonates with arterial duct-dependent CHD and of 40 neonates with respiratory distress without CHD were analyzed on the first, second, third, and fifth day of life.

MAIN RESULTS

Mean aminoterminal B-type natriuretic peptide concentrations in the CHD group were significantly higher on the second (14191 vs. 4872 pg/mL), third (17790 vs. 3524 pg/mL), and fifth day (17015 vs. 4044 pg/mL), but not on the first day of life. Repeated measurements analysis of variance revealed a significantly different time course of aminoterminal B-type natriuretic peptide concentrations between the two groups.

CONCLUSIONS

On the first day of life, aminoterminal B-type natriuretic peptide cannot differentiate between CHD and respiratory distress without CHD in the neonate. From the second day onwards, aminoterminal B-type natriuretic peptide in neonates with CHD shows higher values and a different time course and enables differentiation between CHD and respiratory distress due to other than cardiac reasons.

B-type natriuretic Peptide assay for the diagnosis and prognosis of patent ductus arteriosus in preterm infants

BACKGROUND AND OBJECTIVES

Patent ductus arteriosus (PDA) is a significant cause of morbidity and mortality in preterm infants. Measurement of plasma B-type natriuretic peptide (BNP) has been reported to be a useful bedside screening tool for the presence of hemodynamically significant PDA (hsPDA) in neonates. This study was conducted to investigate the usefulness of a BNP assay as a biochemical marker for the diagnosis of hsPDA and predictive biomarker of the response to indomethacin in preterm infants.

SUBJECTS AND METHODS

Preterm infants born at <37 weeks' gestational age were prospectively enrolled within 24 hours of birth. Plasma BNP levels were measured on days 1, 4, and 7. Significant PDA was diagnosed by large ductal flow with left to right shunt on color Doppler echocardiography, along with clinical features of PDA. Following that, hsPDA was treated with indomethacin.

RESULTS

A total of 28 preterm infants were prospectively enrolled in this study. Seven infants with PDA had higher on day 4 plasma BNP values (median 654.68 pg/mL; range 428.29-1280.00) compared to the control group (median 124.52 pg/mL; range 37.21-290.49). The area under the receiver operator characteristic curve for the detection of hsPDA was high: 0.998 (95% confidence interval: 0.995-1.002). The cutoff of BNP concentration for the diagnosis of hsPDA was determined to be 412 pg/mL (sensitivity: 100%; specificity: 95%).

CONCLUSION

B-type natriuretic peptide can be a useful biomarker for the screening and diagnosis of PDA in preterm infants. Serial BNP measurements are valuable for assessing the clinical course and indomethacin responsiveness of PDA.

Plasma C-type natriuretic peptide levels in healthy children

C-type natriuretic peptide (CNP) is assuming increasing importance in cardiovascular disease, and in adults its plasma levels are related to clinical and functional disease severity. Data are scarce regarding the reference values for CNP in infancy. Aim of this study was to assess the reference intervals for CNP in human healthy newborns and infants. Plasma CNP was measured in 121 healthy children divided into: 41 newborns (age 0-3 days), 24 newborns (4-30 days), 22 infants (1-12 months) and 32 children (1-12 years). A group of 32 healthy adult subjects (age 64 ± 1 years) was also studied. CNP was measured by a specific radioimmunoassay. Between- and within-assay variability resulted ≤ 30 and 20%, respectively and analytical sensitivity 0.77 ± 0.05 pg/tube. Plasma CNP resulted significantly higher in children than in adult subjects (13.6 ± 1.2 pg/ml vs. 7.4 ± 1.0 pg/ml, p=0.030). When the results were analyzed as a function of the age the reference intervals for plasma CNP resulted: 11.6 ± 2.1 pg/ml for newborns (0-3 days), 16.4 ± 3.7 pg/ml for newborns (4-30 days), 15.4 ± 2.7 pg/ml for infants (1-12 months), 13.6 ± 2.3 pg/ml for children (1-12 years) [p=0.01 newborns (4-30 days) vs. adults; p=0.03 infants (1-12 months) vs. adults]. CNP showed the highest concentrations after 12h of life with a peak between 4 and 5 days of life and with a progressive decline afterwards. According to these data at least five different reference intervals for CNP determinations should be used. These observations may be helpful for future clinical application of CNP in human children.

Clinical relevance of time course of BNP levels in neonates with congenital heart diseases

INTRODUCTION

The aim of this study is to better characterize the time courses of BNP levels throughout the first days of life in larger populations of neonate and infant with or without congenital heart diseases (CHD) in order to increase the diagnostic accuracy of BNP assay in pediatric patients with CHD.

MATERIALS AND METHODS

BNP was measured by an automated platform (Triage BNP reagents, ACCESS Immunoassay Systems, Beckman Coulter, Inc., Fullerton, CA 92835) in 218 neonates and infants with different CHD; 222 healthy children, matched for age, served as controls.

RESULTS

BNP values were significantly higher (P<0.001) in the whole group of CHD patients (median 1029.8 ng/L, range 25-20,152 ng/L) than in controls (median 149.5 ng/L, range 9-866 ng/L). A different trend between BNP values and age was observed in healthy subjects and CHD patients. After an initial increase within the first 4 days of life, BNP values in CHD patients tend to stabilize to high values in the following days. On the contrary, in control subjects a peak of BNP levels was observed in the second or third day, followed by a progressive decrease. Therefore, the diagnostic accuracy of BNP assay, calculated in the samples collected in the first four days of life (AUC of ROC analysis 0.86, 95% CI 0.83-0.90) was significantly lower (P<0.0001) compared to samples collected from 5 days to 30 days of life (AUC 0.97, 95% CI 0.95-0.99). Optimal cut-off values for BNP assay, as calculated by ROC analysis, were also age-dependent (cutoff for the first 4 days of life: 363.5 ng/L; cutoff values from 5 to 30 days of life: 109.5 ng/L).

CONCLUSIONS

Our study demonstrates that differences in time-courses of BNP values between newborns with and without CHD throughout the first days of life clearly affect the diagnostic accuracy of BNP assay. Indeed, the diagnostic accuracy of BNP assay in discriminating between healthy newborns and CHD patients progressively increases after the 4th day of life. As a result, also cutoff values of BNP assay greatly change throughout the first days of life. However, decision values of BNP assay are strongly method-dependent, consequently clinicians should give great care to compare results obtained by different laboratories, especially when different methods are used.

Neurohormonal activity and vascular properties late after aortic coarctation repair

BACKGROUND

Coarctation of aorta (CoA) patients present cardiovascular complications late after repair the causes of which are not fully understood. Our study investigates the neurohormonal and immune activation and the elastic properties of the aorta and peripheral vessels in adult patients with coarctation of aorta (CoA), late after repair.

METHODS

Nineteen adult patients with repaired CoA and 29 matched healthy controls underwent aortic distensibility, stiffness index, a study of the elastic properties of peripheral vessels proximal to the coarctation site and measurement of plasma cytokine and neurohormone levels.

RESULTS

Distensibility index was reduced (p=0.02) and stiffness index was increased (p=0.005) in CoA patients compared to control. Augmentation index (p=0.0007) and augmented pressure (p=0.001) were higher in CoA patients and Forearm Blood Flow (FBF) index was reduced (p=0.009). Plasma levels of sICAM-1 (p=0.01), sVCAM-1 (p=0.05), E-selectin (p=0.01), sFas-ligand (p=0.02) and IL-10 (p=0.01) were also elevated in CoA patients vs control. TNF-a, IL-6, Endothelin-1 and NT-pro-BNP levels were not.

CONCLUSIONS

Adults with repaired CoA seem to develop a late inflammatory reaction, which reflects a functional problem in all vessels, regardless of the initial lesion. This may explain the late complications of the disease despite early repair and improved surgical procedures.

Diagnostic, prognostic and therapeutic relevance of B-type natriuretic hormone and related peptides in children with congenital heart diseases

The aim of this article is to review the diagnostic and prognostic relevance of measurement of brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in pediatric patients with congenital cardiac diseases (CHD). A computerized literature search in the National Library of Medicine using the keywords "BNP assay" and "NT-proBNP assay"+neonate/s and newborn/s was performed. Next, we refined the analysis to include only the studies specifically designed to evaluate the clinical usefulness of BNP and NT-proBNP measurements in children with CHD. Several authors suggested that BNP/NT-proBNP is clinically helpful as a diagnostic and prognostic marker for children with suspected CHD. BNP values are age dependent, even in paediatric populations. Unfortunately, accurate reference values for BNP and NT-proBNP for neonatal ages have only recently become available. As a result, the lack of homogenous and accurate decisional levels in the neonatal period greatly limits the clinical impact of the BNP assay, and also contributed to the production of conflicting results. Regardless of age, there is great variability in BNP/NT-proBNP values among CHD characterized by different hemodynamic and clinical conditions. In particular, cardiac defects characterized by left ventricular volume and pressure overload usually show a higher BNP response than CHD which is characterized by right ventricular volume or pressure overload. BNP and NT-proBNP may be considered helpful markers in the integral clinical approach for patients with CHD. Measurement of BNP cannot replace cardiac imaging (including echocardiography, angiography and magnetic resonance), but provide independent, low cost and complementary information for the evaluation of cardiac function and clinical status.

Reference intervals for brain natriuretic peptide in healthy newborns and infants measured with an automated immunoassay platform

BACKGROUND

In order to assess the reference intervals for B-type natriuretic hormone (BNP) in the first days of life, we measured peptide concentrations using the fully automated Access platform.

METHODS

Plasma BNP was measured in 188 apparently healthy newborns and infants throughout the first month of extra-uterine life, as well as in 245 healthy infants ranging from 1 month to 12 years of age.

RESULTS

BNP showed the highest concentrations in the first 2 days of life, with a progressive decline afterwards. Moreover, BNP values in the first week of life were significantly higher (p<0.0001) than values observed in the next periods. As a result, a significant negative correlation was found between BNP and age values when considering all 433 samples (rho=-0.816, p<0.0001 by the Spearman rank correlation test). There was no significant difference between BNP values found in males and females.

CONCLUSIONS

According to this data, our study indicates that at least two reference intervals should be used for newborns and infants. The first, with higher BNP values for neonates in the first week of extra-uterine life, and the other, with lower BNP values for infants aged 2 weeks to 12 years.

BNP concentrations and cardiovascular adaptation in preterm and fullterm newborn infants

To evaluate and compare cardiovascular adaptation of 36 preterm and 34 fullterm newborns, we analyzed BNP concentration and echocardiographic parameters at day 3 of life and at day 28 (+/-2). On day 3 BNP concentrations (pg/ml) resulted higher in PDA preterm group (n=11; 125, IQR 56.1-301) than preterm without PDA (n=25; 25.5 IQR 10.9-49; p<0.001) than fullterms (n=34; 55.1 IQR 23.6-82.7; p=0.013). No difference resulted in all groups at 28days (respectively: 12.7 IQR 4.9-23.8; 15.6 IQR 10-22; 8.9 IQR 5.6-20.6). Because of the newborns' growth, all echocardiographic parameters increased with linear relationship with body weight. On day 3 BNP concentration and echocardiographic parameters were not correlated besides LA/AO in preterms with PDA (p=0.0015). On day 28, BNP was significantly correlated with mVTI (p=0.019), M (p=0.007) and LA (p=0.005) in fullterms and only with LA (p=0.007) in preterms. In conclusion, BNP concentrations and echocardiographic measures confirm that preterm, and fullterm newborns conduct themselves in a similar manner during the transition from foetal to post-natal circulation, reaching low levels at a month of life. The presence of PDA during first days of life has no significant impact in this adaptation. LA is the echocardiographic parameter mostly related to BNP concentration in the newborns.

B-type natriuretic peptide and heart failure in patients with ventricular septal defect: a pilot study

In adults without congenital heart disease, B-type natriuretic peptide (BNP) has been shown to be a very sensitive and specific marker of heart failure. The utility of BNP as a marker of clinical heart failure in children with a ventricular septal defect (VSD) has yet to be determined. A prospective, observational study evaluated BNP levels and other measures of heart failure. Eligible patients were <2 years old, scheduled to undergo surgical repair of a VSD, and without other significant structural heart disease. Data collected before and after surgical repair included echocardiographic measurements, electrocardiographic (ECG) findings, Ross score, BNP measurements, and weight gain. A total of 21 patients were enrolled and 14 patients had complete postoperative follow-up data. For patients with complete data, mean BNP decreased by 94 pg/ml (118 pre vs. 24 post; paired t-test, p = 0.041), mean left ventricular end-diastolic dimension z-score decreased by 1.75 (+0.86 vs. -0.89; paired t-test, p = 0.013), mean weight z-score change per month increased by 0.35 (-0.25 vs. +0.10; Wilcoxon test, p = 0.013), and the incidence of biventricular hypertrophy on ECG decreased (46% vs. 0%; McNemar test, p = 0.031). The change in BNP showed a trend toward a negative correlation with weight z-score change per month (r = -0.531, p = 0.075). In conclusion, BNP, along with other measures of heart failure, decreased following VSD repair, and the change in BNP was most closely correlated with improved weight gain.

Amino terminal pro B-type natriuretic peptide levels are elevated in the cord blood of neonates with congenital heart defect

This prospective study investigates whether amino terminal proB-type natriuretic peptide (NT-proBNP) levels are elevated in neonates with congenital heart defect (CHD). NT-proBNP levels in the umbilical cord blood of 60 neonates with prenatally diagnosed CHD, in the cord blood of 200 control subjects, and in the plasma of the respective mothers were analyzed using an automated enzyme immunoassay. NT-proBNP concentrations in the cord blood of the CHD group were significantly elevated compared with controls [median (range): 158 pg/mL (378-3631 pg/mL) and 626 pg/mL (153-2518 pg/mL); p value <0.001]. The NT-proBNP concentrations of the newborns and their mothers did correlate neither in the CHD nor in the control group. In 54 patients with CHD, NT-proBNP levels were measured on the median 5th day of life. They showed a significant increase (median 1665 pg/mL and 19222 pg/mL; p < 0.001). NT-proBNP levels in the cord blood of neonates with CHD are significantly elevated and show a marked increase in the first week of life. Furthermore, this study confirms previously published reference intervals of NT-proBNP in the cord blood of healthy neonates as well as the finding that there is no exchange of NT-proBNP across the placenta.